Most Near-Earth Objects Won’t Get Here Anytime Soon
What’s the Latest Development?
Donald Yeomans, manager of NASA’s Near-Earth Object Program Office, recently gave a talk discussing his new book, which describes the latest efforts by scientists to find and track near-Earth objects (NEOs). He says that as of early 2012 a team consisting of both professional and amateur astronomers has located 8,800 asteroids and comets whose orbits come within approximately 150 million kilometers of Earth. Ninety percent of those whose diameters are larger than a kilometer have been found and their orbits projected at least a century ahead. Yeomans says that the findings demonstrate “with a very good deal of certainty that no asteroid or comet large enough to threaten life as we know it will hit Earth in the next 100 years.”
What’s the Big Idea?
Although impacts by NEOs are historically rare, they’ve caused catastrophic damage. The asteroid attributed with causing the extinction of dinosaurs and many other forms of surface life was 10 to 15 kilometers across, and created a crater 150 kilometers in diameter. Yeomans says that based on current data, any sizable future NEO headed towards Earth would be detected at least 50 years before arrival, giving humans plenty of time to defend the planet: “The reason the dinosaurs went extinct is because they didn’t have a space program.”
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Read it at Scientific American
